kv-storage implementation for Cloudflare Workers

cf-storage-area.ts

import { Base64Encoder, Base64Decoder } from 'base64-encoding';

const PREFIX = 'data:application/octet-stream;base64,';

const b64e = new Base64Encoder();
const b64d = new Base64Decoder();

const encodeKey = (key: string | BufferSource) => typeof key !== 'string' ? PREFIX + b64e.encode(key) : key;
const decodeKey = (key: string) => key.startsWith(PREFIX) ? b64d.decode(key.substr(PREFIX.length)) : key;

async function* __paginationHelper(db: KVNamespace) {
  let keys: { name: string; expiration?: number; metadata?: unknown }[];
  let done: boolean;
  let cursor: string;
  do {
    ({ keys, list_complete: done, cursor } = await db.list({ ...cursor ? { cursor } : {} }));
    for (const { name } of keys) yield name;
  } while (!done);
}

export class StorageArea {
  db: KVNamespace;

  constructor(name: string) {
    this.db = Reflect.get(self, name);
  }

  async get(key: string | BufferSource) {
    return this.db.get(encodeKey(key));
  }

  async set(key: string | BufferSource, value: string): Promise<void> {
    this.db.put(encodeKey(key), value);
  }

  async delete(key: string | BufferSource) {
    return this.db.delete(encodeKey(key));
  }

  async clear() {
    for await (const key of __paginationHelper(this.db)) {
      await this.db.delete(key)
    }
  }

  async *keys(): AsyncGenerator<string | BufferSource> {
    for await (let key of __paginationHelper(this.db)) {
      yield decodeKey(key);
    }
  }

  async *values(): AsyncGenerator<string> {
    for await (let key of __paginationHelper(this.db)) {
      yield this.db.get(key);
    }
  }

  async *entries(): AsyncGenerator<[string | BufferSource, string]> {
    for await (let key of __paginationHelper(this.db)) {
      yield [decodeKey(key), await this.db.get(key)];
    }
  }
}

Update:

A better implementation is now available as a standalone module here: https://github.com/worker-utils/cloudflare-kv-storage